Wolf species have distinctive howling repertoires that function like dialects, finds the biggest study ever done on canid howling.

A research team from the United States, United Kingdom, Spain and India ran more than 2,000 different recorded howls from 13 canid species and subspecies (the canid family includes wolves, jackals, and domestic dogs) through a software algorithm that boiled them down to 21 howl types (depending on pitch and other characteristics).

They found that different wolf species use the howl types in ways that are specific to them. Timber wolves, for example, use a preponderance of low, flat howls, as opposed to higher vocals used by red wolves.

The scientists said their findings could aid in conservation efforts. For example, while most of the vocal dialects they studied were distinct enough between species to prevent confusion, a few were so similar that they could help fuel interbreeding between different species.

Red wolves and coyotes were such a case. In the study, their howling dialects overlapped significantly.

Efforts to revive populations of the critically endangered red wolf have been stymied due to interbreeding with coyotes. The howling overlap between red wolf and coyote, said study lead Arik Kershenbaum, from the University of Cambridge, "may be one reason why they are so likely to mate with each other, and perhaps we can take advantage of the subtle differences in howling behavior we have now discovered to keep the populations apart."

The researchers also said playback recordings might be used to mimic territorial sounds, perhaps convincing wolf packs to steer clear of livestock.

Kershenbaum and his colleagues think the howling study could also teach us more about the evolution of human language.

"Wolves may not be close to us taxonomically, but ecologically their behavior in a social structure is remarkably close to that of humans. That's why we domesticated dogs: They are very similar to us," said Kershenbaum.

"Understanding the communication of existing social species is essential to uncovering the evolutionary trajectories that led to more complex communication in the past, eventually leading to our own linguistic ability," he added.

Currently, Kershenbaum and colleagues are using new recording methods to try to figure out what the howling types actually mean, what they communicate between animals -- a challenging task, he said, given that it's "virtually impossible" to follow wolf packs in the wild.

The team's work has been published in the journal Behavioural Processes.

Even gray wolves like to cool off in the summer with juicy watermelons, as long as those melons are stuffed with pig ears, cheese and dog biscuits. The Wolf Park in Battle Ground, Indiana raises the canids in captivity for research and educational purposes. Every July, the wolves get a watermelon filled with goodies.

Wolfgang, the watermelon-wielding wolf shown here, gets more than just a snack. He puts his natural instincts and abilities to use when presented with the challenge of digging treats out of a melon.

"Giving the wolves enrichment materials, like watermelons, presents the animals with an opportunity to make choices," Elizabeth Rose, the Wolf Park's managing director, told Discovery News. "Giving animals in captivity the chance to make choices helps reduce boredom and keeps their minds in shape, as well as their bodies."

The Wolf Park opened in 1972 and has held the Watermelon Party for 13 years. The idea for the party came after park staff noted that the wolves were looking longingly at watermelon slices that the humans were eating during a July 4th celebration.

Rose noted that normally the staff don't eat in front of the wolves. However, on that 4th of July someone decided to let the wolf try some watermelon and a tradition was born.